Prime Minister Vladimir Putin's ruling United Russia party won a string of regional elections on Sunday but its support dropped sharply in some areas, results showed on Monday, amid rising anger at inflation and growing unemployment.

Opposition parties said the elections were marred by widespread violations and showed that President Dmitry Medvedev had failed to follow through on a pledge to loosen the Kremlin's grip on the political system.

About 32 million of the country’s 110 million registered voters were eligible to vote in Sunday elections for eight of 83 regional parliaments, five city mayors and dozens of town councils. The turnout in the elections was about 43 percent.

United Russia easily won control of all eight regional parliaments, but its support was down significantly in seven compared with 2007 parliamentary elections.

The party's support fell by about 25 percentage points compared with 2007 in the Urals region of Sverdlovsk to 39.79 percent, results showed. It grew in one region, Voronezh, by 14 percentage points to 62 percent.

In another blow, United Russia was beaten in the election for mayor in the Siberian city of Irkutsk to a candidate from the opposition Communist Party.

"United Russia's popularity is clearly falling due to the crisis," said Nikolai Petrov, an analyst with the U.S.-funded Carnegie Center in Moscow.

United Russia's popularity has taken a hit since the global economic crisis brought an abrupt halt to 10 years of rapid economic growth.

The party spent much of its campaign trying to deflect growing anger over rapid hikes in prices for communal services and growing unemployment, which has sparked a series of large opposition protests in recent months.

Golos, Russia's leading election watchdog, said the election campaign was as dirty as any in recent years, complaining of United Russia's domination of the media.

The electoral commission blocked the opposition Yabloko party from standing in two regional votes after thousands of signatures collected by the party were ruled invalid.

Federal election officials have dismissed opposition complaints of bias and said it had received almost 50 percent fewer complaints than during the last round of regional elections in October last year.

"Of course there were minor violations, but nothing that would effect the results of the elections," senior United Russia parliamentarian Andrei Vorobyov told Vesti-24 television.